WO2019200534A1 - 交流电机绕组温度检测电路、温度检测仪及交流电机 - Google Patents

交流电机绕组温度检测电路、温度检测仪及交流电机 Download PDF

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Publication number
WO2019200534A1
WO2019200534A1 PCT/CN2018/083391 CN2018083391W WO2019200534A1 WO 2019200534 A1 WO2019200534 A1 WO 2019200534A1 CN 2018083391 W CN2018083391 W CN 2018083391W WO 2019200534 A1 WO2019200534 A1 WO 2019200534A1
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Prior art keywords
motor winding
resistor
output
detecting circuit
motor
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PCT/CN2018/083391
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English (en)
French (fr)
Inventor
冯磊
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深圳和而泰数据资源与云技术有限公司
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Application filed by 深圳和而泰数据资源与云技术有限公司 filed Critical 深圳和而泰数据资源与云技术有限公司
Priority to PCT/CN2018/083391 priority Critical patent/WO2019200534A1/zh
Priority to CN201880000903.6A priority patent/CN108780012A/zh
Publication of WO2019200534A1 publication Critical patent/WO2019200534A1/zh

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
    • G01K7/00—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements
    • G01K7/16—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements

Definitions

  • the present application relates to the field of testing equipment, and in particular to an AC motor winding temperature detecting circuit, a temperature detecting device and an alternating current motor.
  • thermometer test method refers to the use of various types of thermometers to directly measure the dimensions of the motor at different positions.
  • the thermocouple test method selectively tests the temperature changes at certain sampling points on the surface of the motor or on the surface of the winding enameled wire by using a thermocouple temperature tester.
  • the prior art has the following problems: when using the thermometer test method, the coil winding temperature inside the motor cannot be measured in real time, and is affected by environmental factors, and the difference between them is large and inaccurate. .
  • thermocouple test method The response time required to determine the thermocouple test method is complicated. Different test conditions will have different measurement results (because it is affected by the heat transfer rate of the thermocouple and the surrounding medium, and the heat transfer rate is high, the thermal response time is short. ). In addition, many motor windings have a metal casing and are not easy to embed.
  • the technical problem that the main solution of the present application mainly solves is that the existing temperature rise test method cannot meet the needs of use well.
  • an embodiment of the present application provides an AC motor winding temperature detecting circuit.
  • the AC motor winding temperature detecting circuit comprises: an AC/DC isolation circuit, a resistance detecting circuit and a processor;
  • the AC/DC isolation circuit is composed of at least one inductor having an input end and an output end; the AC/DC isolation circuit is configured to block an AC current between the input end and the output end and allow a DC current to pass;
  • a detecting end of the resistance detecting circuit is connected to an output end of the AC/DC isolation circuit for generating a voltage signal that changes according to a resistance value of the AC motor winding, and the voltage signal is from the signal of the resistance detecting circuit Output output
  • the processor is coupled to the signal output end of the resistance detecting circuit for receiving the voltage signal and calculating a temperature change of the current AC motor winding according to the voltage signal.
  • the AC/DC isolation circuit includes: a first inductor, a second inductor, and a first capacitor; one end of the second inductor is one of the connection terminals of the input end, and the other end is opposite to the first capacitor One end of the first capacitor is another connection terminal of the input end; one end of the first inductor is one of the connection terminals of the output end, and the other end is connected to the anode of the first capacitor; The other end of the first capacitor is another connection terminal of the output terminal.
  • the AC/DC isolation circuit further includes a load resistor; one end of the load resistor is connected to one end of the first capacitor, and the other end of the load resistor is connected to the other end of the first capacitor.
  • the resistance detecting circuit includes: a bridge detecting unit, an amplifying unit, and a filtering unit; the bridge detecting unit is connected to an output end of the AC/DC isolating circuit through a detecting end of the resistance detecting circuit, according to The resistance value of the AC motor winding changes to generate a corresponding weak voltage signal at the voltage output end of the bridge detecting unit; the amplified signal input end of the amplifying unit is connected to the voltage output end of the bridge detecting unit, and is used for Amplifying the weak voltage signal to form the voltage signal; the voltage signal is output from a signal output end of the resistance detecting circuit; the filtering unit and an amplifying signal input end of the amplifying unit and the resistance detecting circuit The signal output is connected to filter out an interference signal generated during the amplification of the weak voltage signal.
  • the bridge detecting unit includes: a first resistor, a second resistor, a third resistor, and a DC power source;
  • One end of the first resistor is connected to a connection terminal of the output end, and one end of the first resistor further forms a first output pin; the other end of the first resistor is connected to one end of the second resistor, The other end of the first resistor is further connected to the DC power source; the other end of the second resistor is connected to one end of the third resistor, and the other end of the second resistor further forms a second output pin; The other end of the third resistor is connected to the other connection terminal of the output terminal and grounded; when the resistance value of the AC motor winding changes, the corresponding output is weak from the first output pin and the second output pin Voltage signal.
  • the amplifying unit includes: an operational amplifier, a second capacitor, and an eighth resistor; an inverting input terminal and a non-inverting input terminal of the operational amplifier are signal receiving ends, configured to receive the weak voltage signal; An inverting input of the operational amplifier is coupled to an output of the operational amplifier through a second capacitor, and an inverting input of the operational amplifier is further coupled to an output of the operational amplifier through an eighth resistor.
  • the filtering unit includes: a seventh resistor, a ninth resistor, a third capacitor, and a fourth capacitor;
  • One end of the seventh resistor is connected to the non-inverting input end of the operational amplifier, and the other end is grounded; one end of the third capacitor is connected to the non-inverting input end of the operational amplifier, and the other end is grounded;
  • One end of the ninth resistor is connected to the output end of the operational amplifier, and the other end forms the detection signal output end; the other end of the ninth resistor is also grounded through the fourth capacitor.
  • the amplifying unit further includes a fourth resistor and a fifth resistor;
  • the first output pin is coupled to the inverting input of the operational amplifier through the fourth resistor; the second output pin is coupled to the non-inverting input of the operational amplifier through the fifth resistor.
  • the processor is specifically configured to: calculate a change in a resistance value of the AC motor winding according to the received voltage signal; and calculate a temperature change of the AC motor winding according to the change in the resistance value.
  • the processor calculates a temperature change of the AC motor winding by the following formula:
  • ⁇ t is the temperature change of the AC motor winding
  • RCB2 is the current time
  • RCB1 is the initial time
  • t1 is the initial room temperature
  • t2 is At room temperature
  • k is the winding factor.
  • the temperature detector includes an AC motor winding temperature detecting circuit, a detecting terminal, and a display device as described above;
  • the input end of the AC motor winding temperature detecting circuit extends to form a detecting terminal, and the detecting terminal is used for connecting with an AC motor winding of the AC motor;
  • the processor of the AC motor winding temperature detecting circuit is configured to calculate a temperature change of the AC motor winding; the display device is coupled to the processor for displaying a temperature change of the AC motor winding.
  • the AC motor includes a motor winding, a power switch, and an AC motor winding temperature detecting circuit as described above;
  • An input end of the AC motor winding temperature detecting circuit is connected to the AC motor winding, a processor of the AC motor winding temperature detecting circuit is connected to the power switch, and the processor is configured to be used according to a temperature of the AC motor winding Change to control the operation of the AC motor.
  • the AC motor winding temperature detecting circuit in the embodiment of the present application isolates the AC high-voltage on the AC motor side by means of inductive isolation, and can realize real-time online temperature rise test of the AC motor, thereby comprehensively and truly reflecting the real-time operation of the AC motor. happensing.
  • the final temperature rise test result is real-time temperature data during the operation of the AC motor, and the measurement accuracy is high.
  • FIG. 1 is a schematic diagram of a motor winding of a capacitor-operated single-phase asynchronous motor
  • FIG. 2 is a schematic diagram of motor windings of a three-phase asynchronous motor in which stator windings are star-connected;
  • Figure 3 is a schematic diagram of the equivalent resistance of the motor winding shown in Figures 1 and 2;
  • FIG. 4 is a schematic diagram of an application environment of an AC motor winding temperature detecting circuit according to an embodiment of the present application
  • FIG. 5 is a structural block diagram of an AC motor winding temperature detecting circuit according to an embodiment of the present application.
  • FIG. 6 is a circuit schematic diagram of an AC motor winding temperature detecting circuit according to an embodiment of the present application.
  • FIG. 7 is a schematic diagram of an equivalent circuit of an AC motor winding impedance according to an embodiment of the present application.
  • Figure 1 shows a capacitor-operated single-phase asynchronous motor.
  • Figure 2 is a three-phase asynchronous motor in which the stator windings are star-connected. According to Fig. 1 and Fig. 2, it can be seen that the DC resistance at the ends of A and B of the motor winding is the DC winding of the motor winding through which the DC current flows from the A terminal to the B terminal, and the specificity thereof can be equivalent to a corresponding one. Equivalent resistance.
  • an "equivalent resistance” means a fictitious resistor equal to the DC resistance value of the motor winding.
  • Figure 3 is a schematic illustration of the equivalent resistance between the A terminal and the B terminal. As shown in FIG. 3, in the circuit schematic, the equivalent resistance of the motor winding can be represented by a resistor Rx connected between the A terminal and the B terminal.
  • the temperature change of the AC motor winding can be indirectly calculated by measuring the resistance change of the equivalent resistance of the AC motor winding at normal temperature and during operation according to the corresponding resistance-temperature variation formula.
  • the resistance change of the equivalent resistance can be obtained by testing a balanced bridge or the like.
  • a strong AC voltage is applied to both ends of the equivalent resistor, making the bridge test method unusable. Therefore, the resistance measurement of the equivalent resistance must be performed while the motor is stopped. This non-real-time test method will affect the accuracy of the resistance value measurement result and bring inconvenience in use.
  • the AC motor winding temperature detecting circuit provided by the embodiment of the present application can be used to measure the equivalent resistance value of the AC motor winding under the working state, realizing the real-time online change of the AC motor winding temperature. Detection.
  • FIG. 4 is an application environment of an AC motor winding temperature detecting circuit according to an embodiment of the present application.
  • the application environment includes an AC power source 10, an electrical product 20, an AC motor winding temperature detecting circuit 30, a controller 40, a communication module 50, a cloud platform 60, a user terminal 70, and a network 80.
  • the AC power source 10 may specifically be an AC voltage that meets different standards and a frequency power frequency AC power, and the power supply product is connected to provide power for the electrical product 20 .
  • the voltage and frequency of the AC power source 10 are determined by the rated voltage and frequency range actually required by the product. For example, 220V50HZ, 240V50HZ or 120V60HZ.
  • Electrical product 20 is any type of household or industrial electrical device.
  • the electrical product 20 includes at least an AC motor 21 for supplying power and a motor drive circuit 22 for controlling the AC motor.
  • the electrical product 20 may also have other suitable hardware device modules for implementing one or more different functions, such as a housing, a transmission gearbox, and the like.
  • the AC motor 21 may specifically be any suitable type of motor, such as an AC motor as shown in FIG. 2 or FIG.
  • the operating temperature of the AC motor 21 is a very important technical indicator during the operation of the electrical product 20. In the case where the operating temperature is too high, the winding of the AC motor 21 is liable to cause problems such as deterioration in insulation performance and accelerated aging.
  • the motor drive circuit 22 is a switch device for switching the power supply state of the AC motor, for example, a push button switch, a relay, a thyristor device (such as a triac). It can cut or turn on the power according to the control signal or user command.
  • the AC motor winding temperature detecting circuit 30 is a low voltage circuit for measuring the equivalent resistance value of the AC motor winding.
  • the AC motor winding temperature detecting circuit 30 is connected to the motor winding of the AC motor 21 to detect a change in the resistance value thereof.
  • the AC motor winding temperature detecting circuit 30 can be integrated into the electrical product 20 as a functional module to provide a winding temperature detecting function for the electrical product 20.
  • the AC motor winding temperature detecting circuit 20 can also be disposed independently of the electrical product 20, and after being provided with a corresponding housing and interaction device, used as a temperature detector for detecting a plurality of different electrical appliances. The winding temperature of the product 20.
  • the controller 40 can be any type of chip or integrated circuit with certain logic computing capabilities.
  • the controller 40 can be used as one of the functional modules of the AC motor winding temperature detecting circuit 30 to calculate the temperature change of the motor according to the detected change in the resistance value.
  • the controller 40 can also include at least one memory that stores a corresponding computing program that is called by the controller 40 when needed.
  • the controller 40 can also be separated from the AC motor winding temperature sensing circuit 30, with the same function being performed by the main control board of the electrical product.
  • the AC motor winding temperature detecting circuit 20 serves only as a detecting sensor, and provides corresponding sampling parameters to the main control board so that the main control board of the electrical product has the corresponding temperature rise detecting function.
  • the communication module 50 is a hardware function module for establishing a communication connection between the controller 40 or the winding temperature detecting circuit 30 and the outside world.
  • the corresponding hardware module can be selected based on a plurality of different communication methods.
  • the communication module 50 can be a Wi Fi module, a Bluetooth module, a GPRS communication module, or the like.
  • the cloud platform 60 can be an electronic computing platform for providing one or more application services.
  • the cloud platform 60 is provided with hardware support by the server, and the detection signal from the winding temperature detecting circuit 30 is acquired through the network 80.
  • the cloud platform 60 can further push the temperature detection result of the corresponding electrical product to the user terminal 70 through the network 80, and play a reminding role when the temperature is too high, to ensure the safe operation of the electrical product.
  • the AC motor winding temperature detecting circuit 30, the controller 40, and the communication module 50, the cloud platform 60, and the user terminal 70 may constitute an organic component in the smart home, and provide corresponding electrical safety functions.
  • the cloud platform 60 can continuously record the temperature rise parameters of various electrical products in the home. The user can call or view the relevant temperature rise parameter information through the user terminal 70.
  • the cloud platform 60 can also support more intelligent functions, such as pushing the temperature rise parameter into the user terminal 70 in an automatic transmission manner. Or when the temperature of the electrical product rises to a set threshold, the alarm information is automatically pushed or the shutdown protection function is activated to control the automatic shutdown of the electrical product to protect the operation safety of the electrical product.
  • FIG. 5 is a functional block diagram of an AC motor winding temperature detecting circuit 30 according to an embodiment of the present application.
  • the AC motor winding temperature detecting circuit specifically includes an AC/DC isolation circuit 31, a resistance detecting circuit 32, and a processor 33.
  • the AC/DC isolation circuit 31 is composed of at least one inductor and has an input end and an output end.
  • the AC/DC isolation circuit 31 has electrical characteristics that block AC current between the input terminal and the output terminal and allow DC current to pass.
  • the two ends of the winding to be tested are respectively connected to the live line ACL of the AC power source and the neutral line ACN (ie, the zero potential neutral point of the AC power source). Since the AC power applied to the windings during operation of the AC motor destroys and interferes with the analog circuitry used to perform the resistance value detection of the equivalent resistor. Therefore, the AC/DC isolation circuit 31 can be used to connect the input end thereof to the motor winding M to isolate the AC power source loaded on the winding M to be detected, thereby making it possible to detect the resistance value of the equivalent resistance in real time.
  • the AC/DC isolation circuit may include: a first inductor L1, a second inductor L2, and a first capacitor C1.
  • One end of the second inductor L2 is one of the connection terminals A of the input end, and the other end is connected to one end of the first capacitor C1; the other end of the first capacitor C1 is another of the input ends. Connect terminal B.
  • One end of the first inductor L1 is one of the connection terminals C of the output end, the other end is connected to the positive pole of the first capacitor C1; the other end of the first capacitor is the other connection terminal D of the output end.
  • the AC/DC isolation circuit may further include a load resistor R0.
  • One end of the load resistor R0 is connected to one end of the first capacitor C1, and the other end of the load resistor is connected to the other end of the first capacitor C1.
  • the first capacitor may be an electrolytic capacitor having a larger capacitance.
  • the first capacitor is an electrolytic capacitor, a positive pole of the electrolytic capacitor is connected to one end of the second inductor L2 and the load resistor R0.
  • the negative electrode of the electrolytic capacitor is grounded to achieve the above-mentioned AC/DC isolation effect.
  • Fig. 7 is an equivalent circuit diagram showing the equivalent transformation of the impedance of the AC motor winding.
  • RX represents the equivalent resistance of the AC motor winding to be tested
  • R20 and R10 represent the corresponding DC resistance values of the first inductor L1 and the second inductor L2, respectively
  • RO is the resistance value of the load resistor.
  • the temperature change of the AC motor winding can be calculated accordingly.
  • the detection terminal of the resistance detecting circuit 32 is connected to the output terminal of the isolation circuit 31 to generate a voltage signal that changes in accordance with the resistance value Rx of the AC motor winding.
  • the resistance detecting circuit 32 may be a circuit for detecting a resistance value based on a current or a voltage. For example, a common bridge may be used to measure the resistance value RCB between the output terminals C and D.
  • the generated voltage signal is output from the signal output terminal of the resistance detecting circuit and is provided for use by a subsequent functional module.
  • FIG. 5 is a resistance detecting circuit 32 implemented by a bridge circuit according to an embodiment of the present application.
  • the resistance detecting circuit includes a bridge detecting unit 321, an amplifying unit 322, and a filtering unit 323.
  • the input of the bridge detecting unit 321 is the detecting end of the resistance detecting circuit. It is connected to the output end of the AC/DC isolation circuit, generates a corresponding weak voltage signal according to the change of the resistance value of the AC motor winding, and is outputted at the signal output end of the bridge detection unit.
  • the bridge detecting unit is composed of a first resistor R1, a second resistor R2, a third resistor R3, and a DC power source VCC.
  • One end of the first resistor R1 is connected to the output end C, and one end of the first resistor R1 further forms a first output leg 321c.
  • the other end of the first resistor R1 is connected to one end of the second resistor R2, and the other end of the first resistor R1 is also connected to the DC power source VCC.
  • the other end of the second resistor R2 is connected to one end of the third resistor R3, and the other end of the second resistor R2 further forms a second output leg 321d.
  • the other end of the third resistor R3 is connected to the output terminal D and grounded.
  • the first output pin and the second output pin form a signal output end of the bridge detecting unit.
  • the total resistance RCB between the first resistor R1, the second resistor R2, the third resistor R3, and the output terminal CD constitutes a typical bridge circuit having four bridge arms.
  • the bridge circuit has two diagonal ends of 321a/321b and 321c/321d. Among them, the diagonal end of 21a/321b is connected with the DC power supply VCC, and the bridge circuit is balanced to make the voltage difference of the output of the AC motor in the normal temperature state (non-operating state) at the diagonal end of 321c/321d is 0.
  • the DC power source VCC may also be grounded through the filter capacitor C2.
  • the interference signal is filtered by adding a filter capacitor C2.
  • the amplified signal input end of the amplifying unit 322 is connected to the voltage output end of the bridge detecting unit for amplifying the weak voltage signal to form the voltage signal.
  • the voltage signal is output from the signal output of the resistance detecting circuit to the processor.
  • the amplifying unit 322 may specifically adopt any suitable type of voltage amplifying circuit to amplify the weak voltage signal by a specific multiple.
  • the amplifying circuit 33 may be an amplifying circuit based on an operational amplifier or an amplifying circuit based on other semiconductor elements.
  • the amplifying unit 322 specifically includes an operational amplifier U1 , a third capacitor C3 , and an eighth resistor R8 .
  • the inverting input terminal 1 and the non-inverting input terminal 2 of the operational amplifier are respectively connected to the diagonal ends 321c/321d of the bridge detecting unit 321, and receive the weak voltage signal whose following resistance value changes.
  • the inverting input of the operational amplifier is connected to the output 3 of the operational amplifier via a third capacitor C3, and the inverting input of the operational amplifier is also coupled to the output of the operational amplifier via an eighth resistor R8.
  • a current limiting resistor may be connected in series between the inverting input terminal 1 and the non-inverting input terminal 2 of the bridge detecting unit and the operational amplifier to perform a current limiting function. That is, the first output pin 321c can be connected to the inverting input terminal of the operational amplifier through the fourth resistor R4; the second output pin 321d is connected to the positive phase of the operational amplifier through the fifth resistor R5. The input is connected.
  • the third capacitor C3 is a feedback capacitor connected between the inverting input terminal and the output terminal.
  • the amplification factor of the operational amplification unit for the voltage is determined by the resistance value of the eighth resistor R8 and the fourth resistor R4 and the ratio. In the actual application process, the amplification factor of the voltage signal can be adjusted by adjusting the ratio of the eighth resistor R8 and the fourth resistor R4 according to actual conditions.
  • the filtering unit 323 is connected to the amplified signal input end of the amplifying unit 322 and the signal output end of the resistance detecting circuit for filtering out an interference signal generated during the amplification of the weak voltage signal.
  • the filtering unit 323 may include a seventh resistor R7 , a ninth resistor R9 , a fourth capacitor C4 , and a fifth capacitor C5 .
  • one end of the seventh resistor R7 is connected to the non-inverting input terminal 2 of the operational amplifier, and the other end is grounded.
  • One end of the fourth capacitor C4 is connected to the non-inverting input terminal 2 of the operational amplifier, and the other end is grounded.
  • One end of the ninth resistor R9 is connected to the output end of the operational amplifier, and the other end is a voltage signal output end. The other end of the ninth resistor R9 is also grounded through the fifth capacitor C5.
  • the fourth capacitor C4 and the fifth capacitor C5 are used as filter capacitors, which can filter out other interference signals during the amplification process, and ensure that an accurate voltage signal can be outputted at the output of the operational amplifier for subsequent processor calculation.
  • the winding temperature changes.
  • the processor 33 has a corresponding digital or analog signal interface, is connected to the signal output terminal, receives the voltage signal, and calculates a resistance value Rx of the AC motor winding by the formula disclosed in the above embodiment, and calculates an AC motor according to the resistance value.
  • the temperature of the winding changes.
  • the temperature change of the AC motor winding can be calculated by the change of the DC resistance RCB according to the resistance-temperature variation formula.
  • the processor can calculate the temperature change of the AC motor winding by using the following formula:
  • ⁇ t is the temperature change of the AC motor winding
  • RCB2 is the current time
  • the resistance value of the DC resistance RCB ie, the current resistance value
  • RCB1 is the initial time
  • the resistance value of the DC resistance RCB ie, the initial resistance value
  • t1 is the initial room temperature
  • t2 is the current room temperature
  • k is the winding coefficient and is determined by the material of the winding. For example, the copper winding has a k value of 234.5 and the aluminum winding has a k value of 225.
  • the AC motor winding temperature detecting circuit provided in this embodiment is based on the high inductance of the inductor, and realizes a low-cost AC/DC isolation circuit, which can well realize the working voltage of the AC motor and the AC motor winding temperature detection.
  • the isolation between the circuits allows the AC motor winding temperature detection circuit to be tested online in real time.
  • the circuit has a small circuit area and can have a wide range of applications. It can be used as a functional module integrated in the AC motor, so that the corresponding AC motor or electrical product has a corresponding winding temperature detection function, and can also be used as an independent AC motor winding temperature detector is used.

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Abstract

一种交流电机绕组温度检测电路（30），包括：交直流隔离电路（31）、电阻检测电路（32）以及处理器（33）；所述交直流隔离电路（31）由至少一个电感（L1,L2）组成，具有输入端(A,B)和输出端(C,D)用于隔断所述输入端(A,B)与所述输出端(C,D)之间的交流电流并允许直流电流通过；所述电阻检测电路(32)的检测端与所述交直流隔离电路(31)的输出端连接，用于生成跟随所述交流电机绕组的电阻值(Rx)而变化的电压信号，所述电压信号从所述电阻检测电路（32）的信号输出端输出；所述处理器（33）与所述电阻检测电路（32）的信号输出端连接，用于接收所述电压信号并根据所述电压信号计算当前交流电机绕组的温度变化。其可以实现对交流电机（21）的实时在线温升测试，全面、真实的反映交流电机的实时运行情况。还公开了温度检测仪及交流电机（21）。

Description

交流电机绕组温度检测电路、温度检测仪及交流电机 技术领域
本申请涉及检测设备技术领域，特别是涉及一种交流电机绕组温度检测电路、温度检测仪及交流电机。
背景技术
电机的使用寿命、稳定性等均与工作温度之间存在密切的联系。按照国标的规定，不同绝缘等级的电机绕组有不同的允许温升，若电机绕组的温升超过了规定值，会影响电机的使用寿命，严重时会烧坏电机。
因此，必须准确的测定电机额定运行时电机绕组的温度从而检查电机的性能是否合格。现有针对电机中绕组的常规测试方法通常包括温度计测试法和热电偶测试法两种。
其中，温度计测试法是指采用各种不同类型的温度计，直接测量电机在不同位置的维度。热电偶测试法则通过使用热电偶温度测试仪，选择性的测试电机表面或者绕组漆包线表面某些取样点的温度变化情况。
在实现本申请的过程中，申请人发现现有技术中存在如下问题：使用温度计测试法时，不能实时测量电机内部的线圈绕组温度，受到环境因素的影响，相互之间差异较大而不准确。
而确定热电偶测试法所需要的响应时间比较复杂，不同的试验条件会有不同的测量结果(因为它受热电偶与周围介质的换热率影响，换热率高，则热响应时间就短)。另外，很多电机绕组有金属外壳，也不方便埋线进行测试。
发明内容
本申请实施例主要解决的技术问题是：现有的温升测试方法无法很好的满足使用需要。
为解决上述技术问题，本申请实施例提供一种交流电机绕组温度检测电路。所述交流电机绕组温度检测电路包括：交直流隔离电路、电阻 检测电路以及处理器；
所述交直流隔离电路由至少一个电感组成，具有输入端和输出端；所述交直流隔离电路用于隔断所述输入端与所述输出端之间的交流电流并允许直流电流通过；
所述电阻检测电路的检测端与所述交直流隔离电路的输出端连接，用于生成跟随所述交流电机绕组的电阻值而变化的电压信号，所述电压信号从所述电阻检测电路的信号输出端输出；
所述处理器与所述电阻检测电路的信号输出端连接，用于接收所述电压信号并根据所述电压信号计算当前交流电机绕组的温度变化。
可选地，所述交直流隔离电路包括：第一电感、第二电感以及第一电容；所述第二电感的一端为所述输入端的其中一个连接端子，另一端与所述第一电容的一端连接；所述第一电容的另一端为所述输入端的另一个连接端子；所述第一电感的一端为所述输出端的其中一个连接端子，另一端与所述第一电容的正极连接；所述第一电容的另一端为所述输出端的另一个连接端子。
可选地，所述交直流隔离电路还包括负载电阻；所述负载电阻的一端与所述第一电容的一端连接，所述负载电阻的另一端与所述第一电容的另一端连接。
可选地，所述电阻检测电路包括：桥式检测单元、放大单元以及滤波单元；所述桥式检测单元通过所述电阻检测电路的检测端与所述交直流隔离电路的输出端连接，根据所述交流电机绕组的电阻值变化而在桥式检测单元的电压输出端产生对应的弱电压信号；所述放大单元的放大信号输入端与所述桥式检测单元的电压输出端连接，用于放大所述弱电压信号，形成所述电压信号；所述电压信号从所述电阻检测电路的信号输出端输出；所述滤波单元与所述放大单元的放大信号输入端和所述电阻检测电路的信号输出端连接，用于滤除在所述弱电压信号放大过程中产生的干扰信号。
可选地，所述桥式检测单元包括：第一电阻、第二电阻、第三电阻以及直流电源；
所述第一电阻的一端与所述输出端的一个连接端子连接，所述第一电阻的一端还形成第一输出脚；所述第一电阻的另一端与所述第二电阻的一端连接，所述第一电阻的另一端还与所述直流电源连接；所述第二电阻的另一端与所述第三电阻的一端连接，所述第二电阻的另一端还形成第二输出脚；所述第三电阻的另一端与所述输出端的另一个连接端子连接并接地；在所述交流电机绕组的电阻值发生变化时，从所述第一输出脚和所述第二输出脚输出对应的弱电压信号。
可选地，所述放大单元包括：运算放大器、第二电容以及第八电阻；所述运算放大器的反相输入端和正相输入端为信号接收端，用于接收所述弱电压信号；所述运算放大器的反相输入端通过第二电容与所述运算放大器的输出端连接，所述运算放大器的反相输入端还通过第八电阻与所述运算放大器的输出端连接。
可选地，所述滤波单元包括：第七电阻、第九电阻、第三电容以及第四电容；
所述第七电阻一端与所述运算放大器的正相输入端连接，另一端接地；所述第三电容的一端与所述运算放大器的正相输入端连接，另一端接地；
所述第九电阻一端与所述运算放大器的输出端连接，另一端形成所述检测信号输出端；所述第九电阻的另一端还通过第四电容接地。
可选地，所述放大单元还包括第四电阻和第五电阻；
所述第一输出脚通过所述第四电阻与所述运算放大器的反相输入端连接；所述第二输出脚通过所述第五电阻与所述运算放大器的正相输入端连接。
可选地，所述处理器具体用于：根据接收的所述电压信号，计算所述交流电机绕组的电阻值变化情况；根据所述电阻值变化情况，计算所述交流电机绕组的温度变化。
可选地，所述处理器通过如下算式计算所述交流电机绕组的温度变化：
Figure PCTCN2018083391-appb-000001
其中，Δt为所述交流电机绕组的温度变化，RCB2为当前时刻，交直流隔离电路的输出端的电阻值，RCB1为初始时刻，交直流隔离电路的输出端的电阻值，t1为初始室温，t2为当前室温，k为绕组系数。
为解决上述技术问题，本申请另一实施例提供一种温度检测仪。该温度检测仪包括如上所述的交流电机绕组温度检测电路、检测端子以及显示装置；
所述交流电机绕组温度检测电路的输入端延伸形成检测端子，所述检测端子用于与交流电机的交流电机绕组连接；
所述交流电机绕组温度检测电路的处理器用于计算所述交流电机绕组的温度变化；所述显示装置与所述处理器连接，用于显示所述交流电机绕组的温度变化。
为解决上述技术问题，本申请另一实施例提供一种交流电机。该交流电机包括电机绕组、电源开关以及如上所述的交流电机绕组温度检测电路；
所述交流电机绕组温度检测电路的输入端与所述交流电机绕组连接，所述交流电机绕组温度检测电路的处理器与所述电源开关连接，所述处理器用于根据所述交流电机绕组的温度变化，控制所述交流电机的运行。
本申请实施例的交流电机绕组温度检测电路，采用电感隔离的方式隔离了交流电机侧的交流强电，可以实现对交流电机的实时在线温升测试，从而全面、真实的反映交流电机的实时运行情况。最终获得的温升测试结果是交流电机运行过程中的实时温度数据，测量准确度高。
附图说明
一个或多个实施例通过与之对应的附图中的图片进行示例性说明，这些示例性说明并不构成对实施例的限定，附图中具有相同参考数字标号的元件表示为类似的元件，除非有特别申明，附图中的图不构成比例限制。
图1为电容运转式单相异步电动机的电机绕组示意图；
图2为定子绕组为星形连接的三相异步电动机的电机绕组示意图；
图3为图1和图2所示的电机绕组的等效电阻示意图；
图4为本申请实施例的交流电机绕组温度检测电路的应用环境示意图；
图5为本申请实施例的交流电机绕组温度检测电路的结构框图；
图6为本申请实施例的交流电机绕组温度检测电路的电路原理图；
图7为本申请实施例的交流电机绕组阻抗的等效电路示意图。
具体实施方式
为了使本申请的目的、技术方案及优点更加清楚明白，以下结合附图及实施例，对本申请进行进一步详细说明。应当理解，此处所描述的具体实施例仅用以解释本申请，并不用于限定本申请。
在实际应用中的交流电机具体具有多种不同的类型。一般的，可以分为单相电机和三相电机两大类。图1和图2所示的为惯常使用，比较常见的几种交流电机的电机绕组示意图。
其中，图1所示为电容运转式单相异步电动机。图2是定子绕组为星形连接的三相异步电动机。根据图1和图2所示的，可以看出在电机绕组的A、B两端的直流电阻为直流电流从A端到B端所经过电机绕组的直流绕组,其具体可以等效为一个相应的等效电阻。
在本实施例中，以“等效电阻”表示与电机绕组的直流电阻值相等的一个虚构的电阻。图3为所述等效电阻在A端和B端之间的示意图。如图3所示，在电路原理图中，电机绕组的等效电阻可以由连接在A端和B端之间的电阻Rx表示。
基于电阻随温度变化而改变的原理，通过测量交流电机绕组的等效电阻在常温和运行时的阻值变化，根据相应的电阻-温度变化公式，即可间接的计算交流电机绕组的温度变化。
一般的，该等效电阻的阻值变化可以通过平衡电桥等方式测试获得。但由于交流电机在工作时，等效电阻的两端会施加有很强的交流电压，使得电桥测试的方式无法使用。因此，对等效电阻的阻值测量必须要在 电机停机的状态下才能进行。该非实时的测试方式，会影响电阻值测量结果的准确性并带来使用上的不便。
为了避免上述测量方式导致的一系列问题，可以使用本申请实施例提供的交流电机绕组温度检测电路测量在工作状态下的交流电机绕组的等效阻值，实现对交流电机绕组温度变化的实时在线检测。
图4为本申请实施例提供的交流电机绕组温度检测电路的应用环境。如图4所示，在该应用环境中包括：交流电源10、电器产品20、交流电机绕组温度检测电路30、控制器40、通信模块50、云端平台60、用户终端70以及网络80。
交流电源10具体可以是符合不同标准的交流电压以及频率工频交流电，供电器产品接入，用于为电器产品20提供电能。交流电源10的电压和频率具体根据产品实际需要的额定电压和频率范围所决定。例如，220V50HZ、240V50HZ或者120V60HZ。
电器产品20是任何类型的家用或者工用的电器设备。在电器产品20中至少包括用于提供动力的交流电机21以及用于控制交流电机的电机驱动电路22。所述电器产品20还可以具有其它合适的硬件设备模块，用以实现一种或者多种不同的功能，例如机壳、传动变速箱等。
所述交流电机21具体可以是任何合适类型的电机，例如如图2或者图3所示的交流电机。在电器产品20的运行过程中，交流电机21的工作温度是非常重要的技术指标。在工作温度过高的情况下，交流电机21的绕组会容易出现绝缘性能下降，加速老化等问题。
所述电机驱动电路22是用于切换交流电机的供电状态的开关装置，例如，按键开关、继电器、可控硅器件(如双向晶闸管)。其可以根据控制信号或者用户指令，切断或者接通电源。
交流电机绕组温度检测电路30是一个用于进行交流电机绕组的等效电阻值测量的低压电路。该交流电机绕组温度检测电路30与交流电机21的电机绕组连接，检测其电阻值的变化。在本实施例中，所述交流电机绕组温度检测电路30可以作为一个功能模块，整合在电器产品20的内部，为电器产品20提供绕组温度检测功能。
在另一些实施例中，所述交流电机绕组温度检测电路20也可以独立于所述电器产品20设置，设置相应的外壳和交互装置后，作为温度检测仪使用，用于检测多个不同的电器产品20的绕组温度。
所述控制器40可以是任何类型的，具有一定逻辑运算能力的芯片或者集成电路。所述控制器40可以作为所述交流电机绕组温度检测电路30中的其中一个功能模块，根据检测到的电阻值变化来计算电机的温度变化情况。所述控制器40还可以包括至少一个存储器，存储有相应的计算程序，在需要时由控制器40调用。
在一些实施例中，所述控制器40也可以从交流电机绕组温度检测电路30分离，由电器产品的主控制板执行相同的功能。此时，所述交流电机绕组温度检测电路20仅作为一个检测传感器，向主控制板提供相应的采样参数使电器产品的主控制板具备相应的温升检测功能。
所述通信模块50是用于建立控制器40或者绕组温度检测电路30与外界通信连接的硬件功能模块。其具体可以基于多种不同通信方式选择对应的硬件模组。例如，所述通信模块50可以是Wi Fi模组、蓝牙模组、GPRS通信模块等。
所述云端平台60可以是用于提供一种或者多种应用服务的电子计算平台。所述云端平台60由服务器提供硬件支持，通过网络80获取来自绕组温度检测电路30的检测信号。所述云端平台60还进一步的可以通过网络80向用户终端70推送相应的电器产品的温度检测结果，在温度过高时发挥提醒作用，用以确保电器产品的安全运行。
在本应用环境中，所述交流电机绕组温度检测电路30、控制器40以及通信模块50、云端平台60以及用户终端70可以组成智能家居中的有机组成部分，提供相应的电器安全功能。云端平台60可以持续的记录家中各个电器产品的温升参数。用户可以通过用户终端70调用或者查看相关的温升参数信息。
进一步的，所述云端平台60还可以支持更智能化的功能，例如将温升参数以自动传送的方式，推送到用户终端70中。或者当电器产品的温度上升到设定阈值时，自动推送报警信息或者启动关机保护功能， 控制电器产品自动关机，保护电器产品的运行安全。
图5为本申请实施例提供的交流电机绕组温度检测电路30的功能框图。如图5所示，所述交流电机绕组温度检测电路具体包括：交直流隔离电路31、电阻检测电路32以及处理器33。
其中，所述交直流隔离电路31由至少一个电感组成，具有输入端和输出端。该交直流隔离电路31具有隔断所述输入端与输出端之间的交流电流并允许直流电流通过的电学特性。
待测绕组的两端分别与交流电源的火线ACL和零线ACN(即交流电源的零电势中性点)连接。由于在交流电机工作时，加载在绕组上的交流电源会破坏和干扰用于进行等效电阻的电阻值检测的模拟电路。因此，可以利用交直流隔离电路31，使其输入端与电机绕组M连接，隔离加载在待检测绕组M上的交流电源，从而使实时在线的检测等效电阻的电阻值成为可能。
如图6所示，所述交直流隔离电路可以包括：第一电感L1、第二电感L2以及第一电容C1。
其中，所述第二电感L2的一端为所述输入端的其中一个连接端子A，另一端与所述第一电容C1的一端连接；所述第一电容C1的另一端为所述输入端的另一个连接端子B。
所述第一电感L1的一端为输出端的其中一个连接端子C，另一端与所述第一电容C1的正极连接；所述第一电容的另一端为所述输出端的另一个连接端子D。
在一些实施例中，所述交直流隔离电路还可以包括负载电阻R0。所述负载电阻R0的一端与所述第一电容C1的一端连接，所述负载电阻的另一端与所述第一电容C1的另一端连接。
具体的，所述第一电容可以为具有较大电容量的电解电容。在所述第一电容为电解电容时，所述电解电容的正极与所述第二电感L2和负载电阻R0的一端连接。所述电解电容的负极则接地，实现上述交直流隔离的效果。
图7为交流电机绕组阻抗等效变换的等效电路示意图。如图7所示， 以RX表示待测交流电机绕组对应的等效电阻，R20和R10分别表示第一电感L1和第二电感L2的对应的直流电阻值，RO为负载电阻的电阻值。
根据图7所示的连接关系，可以看到在交直流隔离电路的输出端C和D之间测得的直流电阻RCB为：
Figure PCTCN2018083391-appb-000002
由于R10、R20以及R0均为已知量。由此，可以推导计算出RX的电阻值为：
Figure PCTCN2018083391-appb-000003
在确定直流电阻RCB的电阻值变化以后，可以据此计算出交流电机绕组的温度变化。
所述电阻检测电路32的检测端与所述隔离电路31的输出端连接，生成跟随所述交流电机绕组的电阻值Rx而变化的电压信号。所述电阻检测电路32可以是基于电流或者电压进行电阻值检测的电路，例如可以采用常用的电桥测量输出端C和D之间的电阻值RCB。生成的电压信号从所述电阻检测电路的信号输出端输出，提供给后续功能模块使用。
具体的，图5为本申请实施例提供的基于电桥电路实现的电阻检测电路32。如图5所示，所述电阻检测电路包括：桥式检测单元321、放大单元322以及滤波单元323。
其中，所述桥式检测单元321的输入为所述电阻检测电路的检测端。其与所述交直流隔离电路的输出端连接，根据所述交流电机绕组的电阻值变化而产生对应的弱电压信号，并且在桥式检测单元的信号输出端输出。
如图6所示，在一些实施例中，该桥式检测单元由第一电阻R1、第二电阻R2、第三电阻R3以及直流电源VCC组成。
其中，所述第一电阻R1的一端与输出端C连接，所述第一电阻R1的一端还形成第一输出脚321c。所述第一电阻R1的另一端与所述第二电阻R2的一端连接，所述第一电阻R1的另一端还与所述直流电源VCC连接。
所述第二电阻R2的另一端与所述第三电阻R3的一端连接，所述第二电阻R2的另一端还形成第二输出脚321d。所述第三电阻R3的另一端与输出端D连接并接地。
所述第一输出脚和所述第二输出脚形成所述桥式检测单元的信号输出端。
在图6所示的检测电路中，第一电阻R1、第二电阻R2、第三电阻R3以及输出端CD之间的总电阻RCB组成了一个具有四个桥臂的典型电桥电路。该电桥电路具有321a/321b和321c/321d的两个对角端。其中，21a/321b对角端与直流电源VCC连接，通过调节平衡该电桥电路，令交流电机的绕组在常温状态(非工作状态)在321c/321d对角端输出的压差为0。
这样的，当交流电机工作一定时间，交流电机绕组的温度上升以后，交流电机绕组的内阻会发生相应的变化，进而导致等效电阻Rx发生变化。当等效电阻Rx的电阻值发生变化后，相应的直流电阻值RCB会发生变化，从而使得电桥电路的平衡被破坏，在321c/321d对角端将输出跟随等效电阻Rx的电阻值变化的弱电压信号。亦即，在等效电阻的电阻值发生变化时，从所述第一输出脚321c和所述第二输出脚321d输出所述弱电压信号。
在一些实施例中，为了进一步的提高电桥检测单元的稳定性和检测结果的准确程度，所述直流电源VCC还可以通过滤波电容C2接地。通过增加滤波电容C2的方式滤除干扰信号。
所述放大单元322的放大信号输入端与所述桥式检测单元的电压输出端连接，用于放大所述弱电压信号，形成所述电压信号。所述电压信号从所述电阻检测电路的信号输出端输出至所述处理器中。所述放大单元322具体可以采用任何合适类型的电压放大电路，将弱电压信号放大特定的倍数。例如，所述放大电路33可以是基于运算放大器的放大电路或者基于其它的半导体元件建立的放大电路。
请继续参阅图6，在一些实施例中，所述放大单元322具体包括：运算放大器U1、第三电容C3以及第八电阻R8。
所述运算放大器的反相输入端1和正相输入端2分别与桥式检测单元321的对角端321c/321d连接，接收所述跟随电阻值变化的弱电压信号。所述运算放大器的反相输入端通过第三电容C3与所述运算放大器的输出端3连接，所述运算放大器的反相输入端还通过第八电阻R8与所述运算放大器的输出端连接。
在一些实施例中，如图6所示，所述桥式检测单元和运算放大器的反相输入端1和正相输入端2之间还可以分别串联连接限流电阻以发挥限流作用。亦即，所述第一输出脚321c可以通过第四电阻R4与所述运算放大器的反相输入端-连接；所述第二输出脚321d则通过第五电阻R5与所述运算放大器的正相输入端连接。
在图6所示的运算放大单元中，第三电容C3是连接在反相输入端和输出端之间的反馈电容。所述运算放大单元对于电压的放大倍数由第八电阻R8的电阻值和第四电阻R4和比值所决定。在实际应用过程中，可以根据实际情况，通过调整第八电阻R8和第四电阻R4的比值来调整电压信号的放大倍数。
所述滤波单元323与所述放大单元322的放大信号输入端和所述电阻检测电路的信号输出端连接，用于滤除在所述弱电压信号放大过程中产生的干扰信号。
请继续参阅图6，在一些实施例中，所述滤波单元323可以包括：第七电阻R7、第九电阻R9、第四电容C4以及第五电容C5。
其中，所述第七电阻R7一端与所述运算放大器的正相输入端2连接，另一端接地。所述第四电容C4的一端与所述运算放大器的正相输入端2连接，另一端接地。所述第九电阻R9一端与所述运算放大器的输出端连接，另一端为电压信号输出端。所述第九电阻R9的另一端还通过第五电容C5接地。
所述第四电容C4和第五电容C5用作滤波电容使用，可以滤除在放大过程中其它的干扰信号，确保在运算放大器的输出端能够输出准确的电压信号，供后续的处理器计算相应的绕组温度变化。
处理器33具有相应的数字或者模拟信号接口，与所述信号输出端 连接，接收上述电压信号并通过上述实施例揭露的公式计算交流电机绕组的电阻值Rx，并且根据该电阻值，计算交流电机绕组的温度变化。
由于交流电机绕组的电阻值Rx与输出端CD之间的直流电阻RCB之间存在对应关系。因此，为了简化运算，可以根据电阻-温度变化公式，通过直流电阻RCB的变化来计算交流电机绕组的温度变化情况。
具体的，处理器可以通过如下算式计算所述交流电机绕组的温度变化：
Figure PCTCN2018083391-appb-000004
其中，Δt为交流电机绕组的温度变化，RCB2为当前时刻，测量获得直流电阻RCB的电阻值(即当前电阻值)，RCB1为初始时刻，测量获得直流电阻RCB的电阻值(即初始电阻值)，t1为初始室温，t2为当前室温。k为绕组系数，由绕组的材质所决定。例如，铜绕组的k值为234.5，铝绕组的k值为225。
综上所述，在本实施例提供的交流电机绕组温度检测电路基于电感的高感抗，实现成本较低的交直流隔离电路，可以很好的实现交流电机的工作电源与交流电机绕组温度检测电路之间的隔离，令交流电机绕组温度检测电路能够实时在线的进行检测。
而且，整个电路的电路面积较小，可以具有广泛的应用范围，既可以作为整合在交流电机内部的功能模块，使相应的交流电机或者电器产品具有相应的绕组温度检测功能，也可以作为独立的交流电机绕组温度检测仪使用。
通过以上的实施方式的描述，领域的技术人员可以清楚地了解到各实施方式可借助软件加必需的通用硬件平台的方式来实现，当然也可以通过硬件。基于这样的理解，上述技术方案本质上或者说对现有技术做出贡献的部分可以以软件产品的形式体现出来，该计算机软件产品可以存储在计算机可读存储介质中，如ROM/RAM、磁碟、光盘等，包括若干指令用以使得一台计算机设备(可以是个人计算机，服务器，或者网络设备等)执行各个实施例或者实施例的某些部分所述的方法。
以上所述仅为本申请的实施方式，并非因此限制本申请的专利范围， 凡是利用本申请说明书及附图内容所作的等效结构或等效流程变换，或直接或间接运用在其他相关的技术领域，均同理包括在本申请的专利保护范围内。

Claims (12)

  1. 一种交流电机绕组温度检测电路，其特征在于，包括：交直流隔离电路、电阻检测电路以及处理器；
    所述交直流隔离电路由至少一个电感组成，具有输入端和输出端；所述交直流隔离电路用于隔断所述输入端与所述输出端之间的交流电流并允许直流电流通过；
    所述电阻检测电路的检测端与所述交直流隔离电路的输出端连接，用于生成跟随所述交流电机绕组的电阻值而变化的电压信号，所述电压信号从所述电阻检测电路的信号输出端输出；
    所述处理器与所述电阻检测电路的信号输出端连接，用于接收所述电压信号并根据所述电压信号计算当前交流电机绕组的温度变化。
  2. 根据权利要求1所述的交流电机绕组温度检测电路，其特征在于，所述交直流隔离电路包括：第一电感、第二电感以及第一电容；
    所述第二电感的一端为所述输入端的其中一个连接端子，所述第二电感的另一端与所述第一电容的一端连接；所述第一电容的另一端为所述输入端的另一个连接端子；
    所述第一电感的一端为所述输出端的其中一个连接端子，所述第一电感的另一端与所述第一电容的正极连接；所述第一电容的另一端为所述输出端的另一个连接端子。
  3. 根据权利要求2所述的交流电机绕组温度检测电路，其特征在于，所述交直流隔离电路还包括负载电阻；
    所述负载电阻的一端与所述第一电容的一端连接，所述负载电阻的另一端与所述第一电容的另一端连接。
  4. 根据权利要求1所述的交流电机绕组温度检测电路，其特征在于，所述电阻检测电路包括：桥式检测单元、放大单元以及滤波单元；
    所述桥式检测单元通过所述电阻检测电路的检测端与所述交直流隔离电路的输出端连接，根据所述交流电机绕组的电阻值变化而在桥式检测单元的电压输出端产生对应的弱电压信号；
    所述放大单元的放大信号输入端与所述桥式检测单元的电压输出端连接，用于放大所述弱电压信号，形成所述电压信号；所述电压信号从所述电阻检测电路的信号输出端输出；
    所述滤波单元与所述放大单元的放大信号输入端和所述电阻检测电路的信号输出端连接，用于滤除在所述弱电压信号放大过程中产生的干扰信号。
  5. 根据权利要求4所述的交流电机绕组温度检测电路，其特征在于，所述桥式检测单元包括：第一电阻、第二电阻、第三电阻以及直流电源；
    所述第一电阻的一端与所述输出端的一个连接端子连接，所述第一电阻的一端还形成第一输出脚；所述第一电阻的另一端与所述第二电阻的一端连接，所述第一电阻的另一端还与所述直流电源连接；
    所述第二电阻的另一端与所述第三电阻的一端连接，所述第二电阻的另一端还形成第二输出脚；所述第三电阻的另一端与所述输出端的另一个连接端子连接并接地；
    在所述交流电机绕组的电阻值发生变化时，从所述第一输出脚和所述第二输出脚输出对应的弱电压信号。
  6. 根据权利要求4所述的交流电机绕组温度检测电路，其特征在于，所述放大单元包括：运算放大器、第三电容以及第八电阻；
    所述运算放大器的反相输入端和正相输入端为信号接收端，用于接收所述弱电压信号；
    所述运算放大器的反相输入端通过第三电容与所述运算放大器的输出端连接，所述运算放大器的反相输入端还通过第八电阻与所述运算放大器的输出端连接。
  7. 根据权利要求6所述的交流电机绕组温度检测电路，其特征在于，所述滤波单元包括：第七电阻、第九电阻、第四电容以及第五电容；
    所述第七电阻一端与所述运算放大器的正相输入端连接，另一端接地；所述第四电容的一端与所述运算放大器的正相输入端连接，另一端接地；
    所述第九电阻一端与所述运算放大器的输出端连接，另一端形成所述检测信号输出端；所述第九电阻的另一端还通过第五电容接地。
  8. 根据权利要求6所述的交流电机绕组温度检测电路，其特征在于，所述放大单元还包括第四电阻和第五电阻；
    所述第一输出脚通过所述第四电阻与所述运算放大器的反相输入端连接；所述第二输出脚通过所述第五电阻与所述运算放大器的正相输入端连接。
  9. 根据权利要求1所述的交流电机绕组温度检测电路，其特征在于，所述处理器具体用于：
    根据接收的所述电压信号，计算所述交流电机绕组的电阻值变化情况；
    根据所述电阻值变化情况，计算所述交流电机绕组的温度变化。
  10. 根据权利要求9所述的交流电机绕组温度检测电路，其特征在于，所述处理器通过如下算式计算所述交流电机绕组的温度变化：
    Figure PCTCN2018083391-appb-100001
    其中，Δt为所述交流电机绕组的温度变化，RCB2为当前时刻，所述交直流隔离电路的输出端的当前电阻值，RCB1为时刻，所述交直流隔离电路的输出端的，t1为初始室温，t2为当前室温，k为绕组系数。
  11. 一种温度检测仪，其特征在于，包括如权利要求1-10任一所 述的交流电机绕组温度检测电路、检测端子以及显示装置；
    所述交流电机绕组温度检测电路的输入端延伸形成检测端子，所述检测端子用于与交流电机的交流电机绕组连接；
    所述交流电机绕组温度检测电路的处理器用于计算交流电机绕组的温度变化；所述显示装置与所述处理器连接，用于显示所述交流电机绕组的温度变化。
  12. 一种交流电机，包括电机绕组以及电源开关，其特征在于，还包括如权利要求1-10任一所述的交流电机绕组温度检测电路；
    所述交流电机绕组温度检测电路的输入端与所述交流电机绕组连接，所述交流电机绕组温度检测电路的处理器与所述电源开关连接，所述处理器用于根据所述交流电机绕组的温度变化，控制所述交流电机的运行。
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CN108780012A (zh) * 2018-04-17 2018-11-09 深圳和而泰数据资源与云技术有限公司 交流电机绕组温度检测电路、温度检测仪及交流电机

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